484 Invasive Stink Bugs and Related Species (Pentatomoidea)
eggs gave parasitism rates between ≈40 and 80% (Figure 10.5). The parasitism rate had its lowest value
in February, increased from March to August, decreased in September, and peaked in October.
Mbondji Mbondji (2001) explained that the relatively low level of egg parasitism in January and
February was due to farmer practices before harvesting, especially that of plantation weeding and chem-
ical spraying. The study also showed that in Foumbot (Figure 10.6A), as well as in Santa (Figure
10.6B), another location in North-West region of Cameroon, Telenomus sechellensis was the most com-
mon parasitoid species, followed by Trissolcus mopsus and Pediobius sp. Parasitoid abundance peaked
from July to October which is the time of rainy season in this area. The species Anastatus antestiae
was not collected in Santa, and the author suggested that this species might not be adapted to coffee
growing at high elevation (1900 m asl). The strepsipteran Corioxenos antestiae was found locally on
Antestiopsis intricata adults in Western Cameroon, but usually with low stylopization rates (< 1% in
Mbondji Mbondji 2001).
A similar study conducted in Rwanda-Burundi reported the seasonal variations of the three most
important egg parasitoid species of Antestiopsis thunbergii ghesquierei in the area (see below) (Brion
1963). High levels of egg parasitism ranging between ≈35 and 70% were recorded over the year with the
exception of October, which showed a parasitism rate of ≈15% (Figure 10.7). The results also showed
different variations depending on the parasitoid species: Trissolcus sp. was mainly present from January
to June, with a peak in May, whereas Telenomus sechellensis and Gryon fulviventre were present all
through the year although parasitism rates varied. The same study recorded relatively high levels of adult
parasitism by Bogosia rubens. The parasitism rate was variable over the year and reached a maximum
of 50% (Brion 1963).
10.6.2.3.3 Parasitoid Rearing
Mass rearing for production of biological control agents has been attempted on other pentatomid species.
For example, Telenomus sechellensis was reared from eggs of the predatory bug Macrorhaphis acuta
Dallas; and Gryon fulviventre from eggs of M. acuta; the Sudan millet bug, Agonoscelis versicoloratus
(Turton); and the southern green stink bug, Nezara viridula (L.) (Le Pelley 1979). Moreover, these two
parasitoids have shown the ability to develop in unfertilized eggs of Antestia bugs, which can be pre-
served for a longer time than fertilized eggs. This characteristic is sometimes suggested by researchers
to explain the fact that egg parasitoid populations can remain in coffee plantations even outside Antestia
bug reproduction periods (Le Pelley 1979).
In Cameroon, Telenomus sechellensis was the only species reared successfully on other pentatomid
eggs. The species used was Aspavia hastator (F.), which is common on weeds from Compositae and
Amaranthaceae around coffee plantations, notably on Achyranthes aspera L. (Mbondji Mbondji 2001).
Jan020406080100Parasitism rate (%) Number of collected and hatched eggs010002000300040005000Feb Mar AprMayJune July AugSeptOct Nov DecFIGURE 10.5 Seasonal variation of parasites emerging from eggs of Antestiopsis intricata (white bars) and number of
sampled eggs (black line) in Foumbot in the West region in Cameroon (from Mbondji Mbondji 2001).